/* vi: set sw=4 ts=4: */ /* * Mini sync implementation for busybox * * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>. * Copyright (C) 2015 by Ari Sundholm <ari@tuxera.com> * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ /* BB_AUDIT SUSv3 N/A -- Matches GNU behavior. */ //config:config SYNC //config: bool "sync" //config: default y //config: help //config: sync is used to flush filesystem buffers. //config:config FEATURE_SYNC_FANCY //config: bool "Enable -d and -f flags (requres syncfs(2) in libc)" //config: default y //config: depends on SYNC //config: help //config: sync -d FILE... executes fdatasync() on each FILE. //config: sync -f FILE... executes syncfs() on each FILE. //kbuild:lib-$(CONFIG_SYNC) += sync.o //applet:IF_SYNC(APPLET_NOFORK(sync, sync, BB_DIR_BIN, BB_SUID_DROP, sync)) //usage:#define sync_trivial_usage //usage: ""IF_FEATURE_SYNC_FANCY("[-df] [FILE]...") //usage:#define sync_full_usage "\n\n" //usage: IF_NOT_FEATURE_SYNC_FANCY( //usage: "Write all buffered blocks to disk" //usage: ) //usage: IF_FEATURE_SYNC_FANCY( //usage: "Write all buffered blocks (in FILEs) to disk" //usage: "\n -d Avoid syncing metadata" //usage: "\n -f Sync filesystems underlying FILEs" //usage: ) #include "libbb.h" /* This is a NOFORK applet. Be very careful! */ int sync_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int sync_main(int argc UNUSED_PARAM, char **argv IF_NOT_DESKTOP(UNUSED_PARAM)) { #if !ENABLE_FEATURE_SYNC_FANCY /* coreutils-6.9 compat */ bb_warn_ignoring_args(argv[1]); sync(); return EXIT_SUCCESS; #else unsigned opts; int ret = EXIT_SUCCESS; enum { OPT_DATASYNC = (1 << 0), OPT_SYNCFS = (1 << 1), }; opt_complementary = "d--f:f--d"; opts = getopt32(argv, "df"); argv += optind; /* Handle the no-argument case. */ if (!argv[0]) sync(); while (*argv) { int fd = open_or_warn(*argv, O_RDONLY); if (fd < 0) { ret = EXIT_FAILURE; goto next; } if (opts & OPT_DATASYNC) { if (fdatasync(fd)) goto err; goto do_close; } if (opts & OPT_SYNCFS) { /* * syncfs is documented to only fail with EBADF, * which can't happen here. So, no error checks. */ syncfs(fd); goto do_close; } if (fsync(fd)) { err: bb_simple_perror_msg(*argv); ret = EXIT_FAILURE; } do_close: close(fd); next: ++argv; } return ret; #endif }